1. Field of the Invention
This invention pertains to particles of cured silicone material containing mineral oil as a releasable ingredient. More particularly, this invention pertains to a composition for modifying the physical properties of organic rubbers and resins by the controlled release of mineral oil from particles of a cured silicone rubber or gel.
2. Description of the Prior Art
Oils have been incorporated into particles of organic polymers to achieve various results. U.S. Pat. No. 4,814,253, which issued to R. Gruber et al. on Mar. 21, 1989 discloses incorporating a silicone or mineral oil into a particulate organic polymer that is used as a toner for electrophotographic imaging Use of these particles makes a separate silicone oil release fluid unnecessary.
Particulate forms of silicone rubber, including powders, have been used as additives to modify the physical properties of synthetic rubbers and resins. In particular, silicone rubber powder has been added to sYnthetic rubbers and resins as stress relieving agents and to improve water resistance.
While particulate forms of silicone rubber are readily dispersed in organic rubbers and resins, they are not as effective as mineral oils with regard to imparting internal lubricity or improving the wear or abrasion resistance of the material in which they are dispersed. These disadvantages have limited the use of these particles as additives for modifying the physical properties of these rubbers and resins.
When a mineral oil is incorporated into a synthetic rubber that is subsequently blended with an organic resin as a modifier, there may be only a limited degree of compatibility between the oil-filled rubber and the resin, resulting in bleed out of the oil to the surface of the resin.
One objective of this invention is to provide a particulate form of a silicone material which exhibits both excellent lubricity and the ability to absorb impact forces. This combination of properties make the material useful as an additive for modifying the physical properties of various types of materials, including but not limited to various synthetic rubbers, organic resins and lubricants.